Saudi Arabia sent fighter jets and artillery bombardments across the border into northern Yemen Thursday in a military incursion apparently aimed at helping its troubled southern neighbor control an escalating Shiite rebellion, Arab diplomats and the rebels said. The Saudis _ owners of a sophisticated air force they rarely use _ have been increasingly worried that extremism and instability in Yemen could spill over to their country, the world's largest oil exporter. The offensive came two days after the killing of a Saudi soldier, blamed on the rebels. Yemen denied any military action by Saudi Arabia inside its borders. But Yemen's president is a key ally of the Saudis, making it highly unlikely the kingdom would have launched the offensive without tacit Yemeni agreement. A U.S. government official said the Yemenis were not involved militarily in the fighting. The official spoke anonymously because he was not authorized to discuss the matter publicly. The offensive immediately raised concerns of another proxy war in the Middle East between Iran and Saudi Arabia, a key U.S. ally. Shiite Iran is believed to favor the rebels in Yemen while Saudi Arabia, which is Sunni, is Iran's fiercest regional rival. The same dynamic has played out in various forms in Lebanon, where Iran supports the Shiite militant Hezbollah and Saudi Arabia favors a U.S.-backed faction, and in Iraq, where Saudi Arabia and Iran have thrown support to conflicting sides in the Sunni-Shiite struggle. A top Saudi government adviser confirmed "a large scale" military operation underway on the Saudi-Yemeni border with further reinforcements sent to the rugged, mountainous area. - Eric Logan from Bookmarklet

The Shi3a in Yemen and the Shi3a in Lebanon are very different. The author does not seem to understand this. - Itachi

I have read a little about the ethnic and religious make-up of Lebanon. Mostly about Hezbollah, Hamas, Druze and Maronite's. What are the major differences between Lebanese and Yemeni Shi3a ? - Eric Logan

Yemeni Shi3a are primarily Zaydiyya, they follow the madhab of Imam Zayd ibn Ali and really only differ from the majority Sunni population by their insistence that the Khalifa be a descendant of the Prophet Muhammad. There is a branch of the Zaydiyya called the Wasiti who are Ithna-3ishri (Twelver) like the ones in Lebanon and Iran. It isn't clear however from this article whether it is the Wasiti who are fighting or the Zaydiyya, but I wouldn't be surprised with either. The Shia in Yemen and the Sunni are very bitter towards each other. - Itachi

The Saudi's don't start tossing artillery shells and bombs everyday you know. Interesting. - Roberto Bonini from iPhone

Thanks, Mohomed. I will have to read more. Comparative religious studies have always been interesting to me. Book suggestions on these topics gratefully accepted. - Eric Logan